Conditional repression of AUXIN BINDING PROTEIN1 reveals that it coordinates cell division and cell expansion during postembryonic shoot development in Arabidopsis and tobacco.
AUXIN BINDING PROTEIN1 (ABP1) has long been characterized as a potentially important mediator of auxin action in plants. Analysis of the functional requirement for ABP1 during development was hampered because of embryo lethality of the null mutant in Arabidopsis thaliana. Here, we used conditional repression of ABP1 to investigate its function during vegetative shoot development. Using an inducible cellular immunization approach and an inducible antisense construct, we showed that decreased ABP1 activity leads to a severe retardation of leaf growth involving an alteration in cell division frequency, an altered pattern of endocycle induction, a decrease in cell expansion, and a change in expression of early auxin responsive genes. In addition, local repression of ABP1 activity in the shoot apical meristem revealed an additional role for ABP1 in cell plate formation and cell shape. Moreover, cells at the site of presumptive leaf initiation were more sensitive to ABP1 repression than other regions of the meristem. This spatial context-dependent response of the meristem to ABP1 inactivation and the other data presented here are consistent with a model in which ABP1 acts as a coordinator of cell division and expansion, with local auxin levels influencing ABP1 effectiveness.
Braun
Nils
N
Institut des Sciences du Végétal, Centre National de la Recherche Scientifique, Unité Propre de Recherche 2355, Université Paris-Sud XI, 91198 Gif sur Yvette Cedex, France.
Wyrzykowska
Joanna
J
Muller
Philippe
P
David
Karine
K
Couch
Daniel
D
Perrot-Rechenmann
Catherine
C
Fleming
Andrew J
AJ
D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002455:Cell Division / Q000235:genetics*; D049108:Cell Enlargement; D000431:Ethanol / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental; D007210:Indoleacetic Acids / Q000494:pharmacology; D018519:Meristem / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D010937:Plant Growth Regulators / Q000494:pharmacology; D018515:Plant Leaves / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D018520:Plant Shoots / Q000166:cytology / Q000235:genetics / Q000254:growth & development*; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction; D014026:Nicotiana / Q000166:cytology* / Q000235:genetics / Q000254:growth & development
D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011956:Receptors, Cell Surface; C083846:auxin-binding protein 1; D000431:Ethanol